1. Technical Field
The present disclosure relates to an optometric apparatus for subjectively examining (measuring) the visual functions of an examinee's eye.
2. Related Art
A subjective-type optometric apparatus (phoropter or refractor) having a pair of right and left lens chamber units with a test window has been known. This apparatus is disclosed in, for example, JP-A-11-19041 (U.S. Pat. No. 6,048,064). When a refractive error of an examinee's eye is corrected, an accurate examination (a perfectly corrected refractive power test) is conducted for a refractive state of the examinee's eye. In consideration of the powers of former spectacles (or former contact lenses), the complaints of the examinee, and the like, prescription powers of new spectacles (or contact lenses), which provide them with comfortable wearing without fatigue, are determined. In other words, first, responses on appearances of a presented test chart are obtained from the examinee in the perfectly corrected refractive power test. Consequently, perfect correction powers in which the best visual acuity can be obtained are found. Prescription powers are then obtained based on these powers and the like.
In addition, if the examinee's eye suffers a visual dysfunction such as phoria, the visual dysfunction is properly analyzed and corrected. In the apparatus in JP-A-11-19041 (U.S. Pat. No. 6,048,064), a horizontal phoria test, a vertical phoria test, a divergence test (a negative relative vergence test), and a convergence test (a positive relative vergence test), and the like are conducted on the examinee's eye, and the test results (analysis results) are displayed. Based on the display, the examiner calculates prescription values (prescription powers) to correct the visual dysfunction.